Swallow double-click events on menu buttons in Web UI in chrome://bookmarks.

ui/webui/resources/js/cr/ui/menu_button.js

Index: ui/webui/resources/js/cr/ui/menu_button.js
diff --git a/ui/webui/resources/js/cr/ui/menu_button.js b/ui/webui/resources/js/cr/ui/menu_button.js
index 3f084b5f75375a6059bab84a6d59eb48c7c4c92c..e7f9804309c452f633e4dd7c203d809554584023 100644
--- a/ui/webui/resources/js/cr/ui/menu_button.js
+++ b/ui/webui/resources/js/cr/ui/menu_button.js
@@ -44,6 +44,7 @@ cr.define('cr.ui', function() {
     decorate: function() {
       this.addEventListener('mousedown', this);
       this.addEventListener('keydown', this);
+      this.addEventListener('dblclick', this);
 
       // Adding the 'custom-appearance' class prevents widgets.css from changing
       // the appearance of this element.
@@ -162,6 +163,11 @@ cr.define('cr.ui', function() {
           // Don't allow elements further up in the DOM to show their menus.
           e.stopPropagation();
           break;
+        case 'dblclick':
+          // Don't allow double click events to propagate.
+          e.preventDefault();
+          e.stopPropagation();
+          break;
       }
     },